Delivery Devices PA0 Surfactants PA0 Hydrogen Peroxide
Formulations such as cosmetics and pharmaceuticals can be dispensed in a wide variety of vehicles and forms, including powders, capsules, liquids, aerosols, and the like. In particular, the delivery of formulations by the aerosol route is generally considered to take one of three forms: (1) the use of "space sprays", such as spray insecticides and air fresheners, which produce very free sprays capable of evaporating rapidly or floating in the air; (2) the use of sprays such as hair sprays and deodorants, that are intended for continuous film formation; and (3) the use of aerated foams, such as shaving creams, which are produced by the rapid expansion of a propellant through an emulsion.
A variety of dispensers have been described for the purpose of delivering formulations of these various types. See, e.g., H. Mintzer, "Aerosols", Chapter 10 in Pharmaceutical Dosage Forms - Disperse Systems, Marcel Dekker, Inc. pp. 204-220 (1989. Aerosols for oral and nasal therapy are generally said to incorporate medicaments as solids suspended in a propellant. More recent advances in valve and propellant technology are said to provide improved delivery to the throat and nasal areas. Formulations delivered in aerosol form by the use of such devices can often include the use of surfactants. For instance, surfactants are commonly used in nebulizer vehicles to decrease surface tension and thus affect particle size (Mintzer, above, p. 206).
Yet other types of aerosol containers, pressurized with nitrogen, have been used to dispense toothpaste through a dip tube and foam-style valve. For a variety of reasons, however, such containers have not been commercially successful. See, e.g., D. Garlen, "Toothpastes", Chapter 14, pp. 511-532 in Pharmaceutical Dosage Forms - Disperse Systems, Marcel Dekker, Inc. 1989. As a result, various forms of "pump" dispensers have been developed for delivering toothpaste, the pumps relying on the use of a spring device to force the toothpaste out of a spout.
Tobler, in U.S. Pat. No. 5,048,750 describes an apparatus that is capable of producing and dispensing foams. The apparatus involves the use of a mounting section covered by a cap that can be displaced from an open position to a closed position. The mixing section involves the use of a pervious planer and air and liquid passages directed to the mixing element.
On a separate subject, a large number of surfactants, including sodium lauryl sulfate ("SIS"), have been widely used and found safe in a variety of cosmetic products, including dentrifices. See, e.g., "Surfactants in Oral Hygiene Products", pp. 299-347 in Surfactants in Cosmetics, M. Reiger ed., Marcel Dekker, Inc. 1985.
As of 1992, SIS itself was present in over 500 oral solid dosage forms approved by the FDA, as well as in 11 oral liquid dosage forms, 38 topical creams, lotions, ointments, medicates sponges or shampoos, and 28 dentrifices. CRC Handbook of Food, Drug and Cosmetic Excipients, S. Smolinske, pp. 359-362 (1992). The usefulness of sodium lauryl sulfate as a synthetic detergent in toothpaste has been studied in a recent article by P. Barkvoll. ("Should toothpastes foam? Sodium lauryl sulfate - a toothpaste detergent in focus", Norske Tannlaegeforenings Tidende 99(3)82-4 (1989)).
U.S. Pat. Nos. 4,657,758 and 4,666,708, for instance, describe dental rinses for loosening plaque and preventing plaque build-up. The rinses described in both patents rely on the detersive effect of oral surfactants. The '708 patent describes the use of SLS as one such oral surfactant, and further describes its function as a "potentiator" for other ingredients. In the Examples, patients were instructed to use one tablespoon of various rinses. Such rinse products, which are commercially available under the brand name "Plax", are typically swirled in the mouth in order to produce a weak foaming action.
On yet another subject, hydrogen peroxide is a common ingredient in mouthwashes and gargles. (See, e.g., "Mouthwashes and Gargles", p. 1680, in American Hospital Formulary Services - Drug Information 1992, G. McEvoy et al. eds., American Society of Hospital Pharmacists). Hydrogen peroxide functions as a weak antibacterial agent, a wound cleanser and a deodorant. It also serves a mechanical effect of effervescence and resultant removal of tissue and other debris.
When used as an oral topical, however, hydrogen peroxide is typically administered in the form of a concentrate, solution, or gel. The product is used for cleansing minor wounds, or minor gum inflammation resulting from dental procedures, orthodontic applications, denture irritations, accidental injury and other mouth and gum irritations (e.g., canker sores).
Such beneficial uses of hydrogen peroxide include its use as an oral germicide, cleansing agent and hemostat. It is considered a useful disinfectant for mucous membranes because of its low toxicity. See, e.g., Zinner. D. D., et. al.; Controlled Study of the Clinical Effectiveness of A New Oxygen Gel on Plaque. Oral Debris and Gingival inflammation, Pharmacol. Ther. Dent., October 1970, 1:7-15.
Dental products such as "MentaDent", which was recently introduced by Chesebrough-Ponds, relies on the use of hydrogen peroxide. The commercial product identifies related U.S. Pat. Nos. 4,687,663, 4,964,539, 5,020,694, 5,038,963, 5,059,417, and Design Pat. No. D 315,496. Such patents relate variously to the use of a hydrogen peroxide component with a second component containing sodium bicarbonate; to a dentifrice composition containing, inter alia, hydrogen peroxide and a polyoxyethylene-polyoxypropylene copolymer; to multi-cavity or multi-chamber dispensing containers; and to a design for a dispensing container.
SLS and hydrogen peroxide have, on occasion, been used together in formulations for the oral cavity. See, for instance, U.S. Pat. No. 5,104,644 and 5,174,990 (mouthrinse), 5,084,268 and 5,208,010 (tooth whitening dentifrice).
There appear however to be few, if any, instances of the use of devices for the propellantless delivery of formulations to the oral cavity in the form of foams, particularly for formulations that incorporate hydrogen peroxide and are used in the oral cavity.